A Look Back at the 1993 World Trade Center Bombing Investigation

On the morning of Feb. 26, 1993, a massive truck bomb ripped a hole almost 100 feet across the B-2 level of the parking garage beneath the World Trade Center's North Tower. The blast wave was so powerful that it penetrated five stories of the reinforced concrete building. In addition to causing structural damage, the explosion destroyed or heavily damaged hundreds of vehicles parked in the garage. That such a powerful explosion killed only six people is nothing short of miracle, for the attackers had a goal much more grandiose.

They wanted to topple the North Tower onto the South Tower to destroy them both and kill thousands. Had a device of the same magnitude been detonated at street level during rush hour, it would have likely killed scores if not hundreds of people and wounded perhaps thousands more.

From Yemen To New York City

An hour or two after the bombing, I landed in Frankfurt, Germany, on my way back to Washington from Yemen. I was working as a Special Agent for the Diplomatic Security Service investigating a bombing attack against U.S. Air Force personnel in Aden on Dec. 29, 1992, and a rocket attack against the U.S. Embassy in Sanaa in January 1993. As I stood in the airport terminal looking at the first reports of the World Trade Center bombing, I had no idea the attack was linked to the incidents I had been investigating in Yemen. Later it would be discovered that the same group that conducted the Yemen attacks also bombed the Trade Center: al Qaeda.

I had initially flown to Yemen with a colleague from the explosives section of the FBI laboratory to investigate the strikes against U.S. interests there. We suspected the Libyans might have conducted those attacks after seriously wounding embassy communicator Arthur Pollick in a 1986 shooting in Sanaa and conducting a series of other attacks against U.S. interests around the world.

One of the explosive devices in the Aden attack had failed to detonate, and we wanted to examine it to see if it matched any of the components or bomb-making signatures from devices used in previous Libyan and Libyan-sponsored attacks. However, after examining the Aden device and the manner in which the rocket attack against the U.S. embassy had been conducted, we were fairly certain the attacks were not the work of the Libyan intelligence service or one of its usual proxies such as the Abu Nidal Organization or the Japanese Red Army, also known as the Anti-Imperialist International Brigade.

But the manner in which that attacks were conducted did tell us one important thing: The CIA had trained whoever had conducted them. Several specific elements of those attacks matched techniques I had learned when I attended the CIA's improvised explosive device training course. (Agents assigned to my office attended the bomb-making course because knowing what is required to make a bomb is crucial when investigating a bombing.) After the CIA station chief assured us that he and his people were not behind the Aden and Sanaa attacks, we concluded that the attackers were most likely Yemenis who had traveled to Afghanistan to fight against the Soviet occupation and had received some training from the CIA's Office of Technical Services — or someone it had trained.

So we knew what the attackers were — jihadists who had returned from Afghanistan — we just didn't have a name for them yet. It would be almost a year before I heard the term "al Qaeda" and a several months after that before I realized the term was the name of a group of former mujahideen who fought in Afghanistan and had turned their sights against the United States.

As I watched the newsfeed in Frankfurt, I also had no idea that I would spend the next two years of my life investigating the World Trade Center bombing and the New York Landmarks bomb plot that was connected to it, which targeted the Lincoln Tunnel, the United Nations Headquarters and the Javits Federal Building in Manhattan among other locations. In fact, since I was returning from a 10-day investigative trip in Yemen, I figured that if my office was asked to assist in the investigation, my supervisor would assign another agent to the case.

But I was wrong. When I arrived home Feb. 27, I found a message on my answering machine telling me to pack my gear for an indefinite rotation to New York. One of my colleagues had been designated to run the case, but he had become tied down at headquarters handling the myriad of investigative leads being sent to regional security officers at U.S. embassies around the world, and he had requested that I be sent to New York to help with the investigation.

A World Trade Center bombing crime scene identification badge issued by the New York JTTF.

Initially, the FBI's working hypothesis was that Serbian terrorists had carried out the bombing in revenge for U.S. support of the republics that had broken away from the former Yugoslavia. Regional security officers at U.S. embassies all over the world were pulling visa applications, airline manifests and crew lists of merchant ships with Serbians on board in an effort to identify the potential bombers. I was skeptical of the idea that Serbians carried out the attack, and my previous experience investigating large vehicle bombings by Hezbollah, such as the March 1992 bombing of the Israeli Embassy in Buenos Aires, led me to suspect that this was another of its attacks. Of course, we would all be proven wrong within a week.

The Crime Scene

I did not deploy to New York alone. The FBI laboratory requested that we transport one of the State Department's EGIS explosive detection machines to the crime scene, and a security engineering officer from the Diplomatic Security Service traveled up to the World Trade Center with me. We arrived in New York at an opportune time on Sunday, Feb. 28. As I checked in with some of my Bureau of Alcohol Tobacco and Firearms (ATF) and NYPD friends at the crime scene, they excitedly told me how they had just found the rear differential of a vehicle that showed indications of heavy explosive pitting and gas wash — signs that it had been in intimate contact with the explosives, or possibly was from the rear end of the vehicle used to transport the bomb.

They documented their find and placed it on an ambulance gurney to take it to the NYPD explosives laboratory in hopes of recovering the vehicle identification number from the differential. The sight of a gurney being wheeled out of the parking garage and loaded into a truck led the press to speculate that another victim had been found. It was a good thing the NYPD and ATF personnel had identified and removed the differential Sunday, because on Monday morning, a huge slab of concrete fell from the level above right onto the area where it had been. Had the agents not moved the differential, it might have been buried for some time.

The excitement my ATF colleagues felt over the differential find became somewhat dampened as they learned of events that transpired in Waco, Texas, earlier that day. A group of Branch Davidian members had holed themselves up in their compound and killed four ATF agents during a raid. The next morning, we all reported for work with black bands over our badges to mourn the agents who lost their lives in Waco.

Diplomatic Security Service Special Agent Scott Stewart uses an EGIS explosive detection machine to examine rubble in the World Trade Center's basement in 1993.

Monday morning was also when we fired up the EGIS machine and ran its collector over several items that appeared to have been in close proximity to the seat of the blast, including a huge steel girder that had been hurled into the Port Authority office where four of the victims were killed. The machine's mass spectrometer showed a substantial spike of some sort of nitrate compound, but the machine had only been programmed to recognize six different common explosive compounds, so it could not identify what it had detected. Laboratory tests would later determine that the main charge was comprised of urea nitrate.

The EGIS machine turned out to be pretty much useless, so I volunteered to help with the rest of the crime scene investigation. I was given a broom and shovel to help the army of police officers and agents working at the site collect bits of rubble, vehicles and other miscellaneous materials so they could be sorted and catalogued at an armory in Long Island. Literally sweeping the crime scene proved to be a long, labor-intensive process.

A few days later, I came off of broom and shovel duty after lab techs were able to pull up the VIN number from the differential and trace it to a Ryder truck that had been rented by Mohammed Salameh. He was known to be a member of a group the FBI had previously investigated as a possible terrorist threat after one of its members assassinated Meir Kahane, the founder of the Jewish Defense League, in a Manhattan hotel in November 1990. Our New York field office was familiar with the group after working with the Manhattan District Attorney's office to investigate overseas leads in the Kahane investigation.

Officers and agents from the New York Joint Terrorism Task Force (JTTF) arrested Salameh at a Ryder rental office March 4. He had filed a stolen vehicle report for the truck and was attempting to retrieve his security deposit. After detaining him, agents and police officers began rounding up his associates identified in the earlier investigation.

One of those associates, Ibrahim Elgabrowny, attacked a colleague of mine from the ATF who was serving a search warrant on his home. Authorities arrested Elgabrowny for assault, and a search team discovered Nicaraguan passports bearing the photos of his cousin, Kahane's assassin El Sayyid Nosair, and his family in addition to Nicaraguan driver's licenses and identification cards. I talked to the JTTF unit supervisor and told him I was confident I had enough to make a passport and document fraud case against Elgabrowny. Because there was no other evidence tying Elgabrowny to the bombing investigation, the JTTF supervisor told me to approach the U.S. Attorney's office to see if it was interested in pursuing the passport fraud case. It was, and Elgabrowny was soon indicted on assault and passport fraud charges.

I quickly developed a close working relationship with the group of assistant U.S. attorneys working the case. They frequently came to me seeking the Diplomatic Security Service's help with some of the more problematic suspects in the World Trade Center bombing case and the connected New York Landmarks plot.

In addition to helping with the successful prosecution of Elgabrowny, Diplomatic Security Special Agents tracked and arranged for the capture and rendition of Mahmud Abouhalima, who had fled the United States after the bombing. We also uncovered sufficient evidence to help tie Ahmed Ajaj to the conspiracy and found critical information that helped the U.S. Attorney convince the U.S. Attorney General to allow the indictment of Sheikh Omar Abdel Rahman. I developed a visa fraud case against Rahman so he could be arrested if acquitted on the seditious conspiracy charges, and we also obtained an indictment for Abdel Basit, also known as Ramzi Yousef, for passport fraud and captured him in Pakistan.

Looking Back

In retrospect, Nosair's assassination of Jewish Defense League founder Meir Kahane was the first notable grassroots jihadist case in the United States. When the FBI infiltrated a group of Nosair supporters, it judged them to be inept and not posing a serious threat. The 1993 World Trade Center case serves as an example of how seemingly bumbling grassroots jihadists or "Kramer Terrorists" can become quite deadly when they link up with a highly trained terrorist facilitator who can lead and organize them. After learning lessons from this case, today, even when a group appears to be somewhat inept like the group of Nosair supporters, the authorities must go after them as hard as they can with whatever charges available instead of just writing them off.

The pre-9/11 terrorism operational model seen in the Kahane assassination, the World Trade Center bombing and the New York Landmarks plot shares many parallels with the current environment. It is far harder for jihadist groups such as al Qaeda or the Islamic State to conduct a 9/11-style attack using highly trained operatives dispatched from overseas to conduct attacks in the United States and the West. The big difference between 1993 and today is that we are now acutely aware of who the jihadists are, be they members of al Qaeda, the Islamic State or other organizations. We also know what they believe and have a clearer idea of their capabilities. There is much more emphasis on countering the threat than there was in 1993. Security agencies also have more resources now.

Finally, my involvement in the investigation of the 1993 bombing gave me a profound sense of the sheer magnitude of the events that occurred on 9/11. I had seen firsthand how a large truck bomb that caused substantial damage in the parking garage had little impact on the twin towers themselves. Seeing the towers completely destroyed was something almost impossible for me to imagine.

I am person with a sheepdog-like wiring that gives me a deep need to protect others, and the time I spent working in the bowels of the World Trade Center and the many months of effort I put into helping catch and prosecute those responsible for the attack also gave me a special affinity for the buildings. Watching the Twin Towers fall on live television impacted me in a deep and personal way — and I am sure that my colleagues from the wide array of agencies involved in the 1993 investigation shared those same feelings of disbelief, grief and shock. New York and the country have moved on from the loss of the World Trade Center, but even today, there is a hole in my heart when I gaze at the Manhattan skyline.

This article is republished with permission of Stratfor. The views and opinions expressed herein are the author's own, and do not necessarily reflect those of EconMatters.